Method of agglomerating finely-divided material.



H. RODMAN.-

METHOD OF AGGLOMERATING FINELY DIVIDED MATERIAL APPLICATION FILED SEPT. 5. 1916.

L gfigl v. JPatentedSept. 4, 1917.

HIS ATTORNEYJIN FACT HUGH RODMALL OF EDGEWOOD, PENNSYLVQNIA, ASSIGNOR TO THE RODMAN JHEMI- CAL (10., A. CORPORATION OF PENNSYLVANIA.

METHOD OF AGGLOMERATING FINELY-DIVIDED Specification of Letters Patent,

' Patented se t. a, ram.

\ Application filed September 5, 1916. Serial No. 118,4.72.

To all whom it may concern;

Be it known that I, HUGH Borrow, a citizen of the United States, and a resident of Edgewood, in the county of Allegheny and State of Pennsylvania, have made a new and useful Invention in Methods of Agglomerating Finely-Divided Material, of which the following is a specification.

This invention relates to the pebbling or agglomerating of powdered material and discloses a new and improved process therefor.

In agglomerating or ebbling crushed or finely divided material y tumbling it with a binding agent it has generally been necessary to employ batch methods and to screen out the oversize and undersize pebbles for reprocessing.

For instance pills have been made by alternately moistening and dusting small nuclei or centers till pills of the average size desired were produced. Over size and undersize pills were then removed and the process repeated.

I secure a continuous process and avoid the screening of the batch process by using a tumbling or agitating device so operated that there is amarked grading action of the material being processed, and with the feed so arranged that the agglomerating or building up takes place only upon the un dersize being out of the building up zone and, preferably, being continuously removed. In this way I secure a more efficient method of manufacturing and a far greater uniformity of product than can be gotten from the old atch method, or froma method in which the grading action is not taken advantage of.

The method 1 have described may be carried forward in several mechanical ways but the way I find best suited to the purpose is as follows:

A tub about two feet deep and two feet diameter with parallel sides is mounted to revolve upon its axis held at about thirty degrees from the horizontal. Finely divided material and binding agent are fed into this device by screw conveyor and sprinkler, or in any suitable way, care being taken to insure the binding agent falling only upon the material tumbling at the back or bottom of the tub. Nuclei may be added unless the tumbling material makes its own nuclei. The size and number of the nuclei L o by screening pills, the pills of full size meantime formed by the tumbling mass maybe regulated by, varyin the amount of binding agent added. The tumbling material rapidly and completely separates into a uniformlygraded mass, all of the larger pills or agglomerates coming to the elevated or outer portion of the tub and grading from there, through smaller and smaller agglomcrates, to the back or bottom of the tub where only the smallagglomerates and-finely divided material or dust remain. It follows that if the binding agent is applied only to the region or zone occupied by the very small agglomerates and dust there will be no building up of any but the small agglomerates and that these, as soon as they are larger than other agglomerates in the /tub; will travel rapidly out of the building up zone. In this way the agglomerates are produced of very uniform size, only those being acted upon which are smaller than others.

As an improved method of manufacturing pills or agglomerates I make use of the proc ess described to secure a continuous manufacturing method rather than a batch process, though the method of building up only the small size agglomerates may also be used as a batch method. For continuous manufacturin I use. the device described, continuously ceding the binding agent into the back of the tumbling mass and continuously feeding the powdered material into the mass somewhat nearer the mouth of the tub and letting the finished pills or agglomerates continuously discharge over tub. I find the best place to spray or sprinkle the binding agent is vertically over the lower edge of the bottom of the tub, and the best place to feed the powdered mate rial to be about half way back from the mouth of the tub. Any excess powder will be quickly carried to the bottom of the tub and will not escape with the finished pills. Nuclei may be added if the material does not form its own.

I have used the device described to. make small agglomerates or pills for carburizing steel, the powder being a mixture of finely divided carbonaceous materials and alkaline materials and the binding agent being molasses solution, glutrin, etc. I have also used the device to make agglomerates of other materials, as starch, macaroni flour, etc.

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the lip of the 0 straight sided tub carries the larger agglomerates to the upper edge of the tub, where the mass is shallowest. I might add that the ordinary tumbling barrel made of the frustum of a cone .and revolved upon its axis held at an angle of about thirty degrees from the horizontal, just about balances the two grading tendencies already described, so that there is little or no grading action Obtained from these commercial machines. That is the shape of the device tends to force the larger a glomerates to the bottom of the frustum, W 1le the angle of the axis tends to force them to the mouth and the two tendencies closely balance.

I believe that I am the first to make use of a process of making agglomerates or pills in which the agglomerates are graded as they.

are formed, and in which the smaller agglomerates only are subjected to the buil mg up action. In other words I believe that I am the first to make agglomerates or pills, in which the agglomerates are aded as formed, the larger agglomerates eing removed or moved out of the building up zone and the smaller agglomerates only being subjected to the bullding up action of the binding agent and dust or finely divided material.

I have shown in the accompanying drawing a device which may be employed in carr ing out my improved process.

- Tlie device includes a tumbling barrel 3 having parallel sides and a diameter about equal to its depth. This is arranged to revolve upon its axis held at about 30 from the horizontal. A spraying or dripping device 4 is mounted so as to mtroduce a binding agent into the barrel and near the inner end thereof. Finely divided or pow I dered material, which may include nuclei if desired, is introduced into the barrel by means of apparatus such as a screw con-. veyer 5, which delivers the dry material at a point about midway between the inner end and the lip of the barrel. The larger agglomerates, as formed, move to the front 0 the barrel and, in a continuous process discharge over the lip of the barrel, whereas the dust and smaller agglomerates move to or remain at the inner end of the barrel and are eventually built up into agglomerates of such size that they move to the front of the.

barrel and are discharged. The final size of agglomerates discharged may be closely regulated by the number and size of nuclei pills or agglomerates, which consists in agltating finely divided material and'nuclei in a grading device, continuously adding" a binding agent to the smaller agglomerates only, and continuously remoying the larger agglomerates.

3. The method of building up pills or agglomerates which consists in tumbling finely divided material and nuclei in a tumbling and grading device and adding a binding agent only to the smaller of the agglomerates formed.

4. The continuous method of building up gills or a glomerates which consists in tumlin fine y divided material and nuclei in a tum ling and grading device, continuously adding a binding agent to the smaller agglomerates onl and continuously removing. the larger agg omerates.

5. The method of building up ills or a lomerates which consists in tum ling fine y ivided material and nuclei in an inclined tumbling and grading device and adding a bllidlllg agent to the smaller agglomerates on y.

6. The process of producing agglomerates, which consists in agitating dry finely divided material and nuclei, in adding a liquid binding agent to the agitated mass, causing the agglomerates -to move away from the zone receiving the bindin agent as they increase in size and finally ischarging the agglomerates from the agltated mass.

7. The process of forming agglomerates, which consists in agitating finely divided material, continuously introducing a binding agent into a definite zone of ag1tation of the mass grading the agglomerates formed by causing them to move farther away from the zone receiving binding agent as they increase in size, and addin additional .quantities of dry material to't e agitated mass at a zone other than the zone receiving the binding agent.

8. The process of increasing the'size of agglomerates which consists in agitating a mass of nuclei and finely divided material, introducing a bindin agent to a definite zone of ag1tation of t e mass and grading the agglomerates as they are formed, by moving them so that the smaller agglomerates only are subjected to the building up 9. The process of increasing the size of agglomerates, which consists in agitatin a mass of nuclei and finely divided materlal,

ading the agglomerates as they are formed y moving agglomerates of different sizes to different zones of agitation and subjecting the smaller agglomerates only to the building up action of a binding agent and finely divided dry material.

. 10. The method of producing pebbles which consists in agitating fine material and the larger agglomerates as formed to travel in one direction, while the smaller agglomerates and fine material travel in another direction, and subjecting the smaller agglomerates only to the action of a finely divided material and binder.

11. The method of producing pebbles which consists in agitating fine material in a ed of varying depth and causing the larger pebbles as formed to travel toward the shallow edge of the bed, subjecting the deeper portion of the bed to the action of a binding agent, and removing the larger pebbles formed from the shallow edge of the bed.

12. The method of agglomerating material which consists in maintaining a mass of fine material in a bed 0 varying depth, addagglomerates, agitating the mass and causing a continuous flow of the smaller agglomerates and material toward the deeper portion of the bed and the larger agglomerates of material toward the shallower portions of the bed, in removing the larger agglomerates and wetting the smaller agglomerates only with binding agent while continuing the agitation.

In testimony whereof, I have hereunto subscribed my name this 2nd day of September, 1916.

HUGH RODMAN. 

